Steaming my christmas pudding

[Anotherunimaginativeusername]

I've got some plastic lidded pudding basins which going to cook my xmas pud in today (I know, I'm 24 hours late for stir-up Sunday). My question is, as they have plastic clip on lids, do I still need to do the pleated foil/paper business, or can I just whack the lids on and steam? Not over filling them to allow for a little expansion of the filling.
I'm going to steam them in my slow cooker, to avoid hob boiling dry issues and it means I can go out for the school run while they cook.

Hope you got them done! FWIW, I'd have just put the lids on and steamed (also in slow cooker, for same reasons).

I did, thank you! They smell awesome, its going to be a struggle to wait till 25th December!